The Resistance is made up of those who survived the initial attacks by the aliens.This includes civilians and members of the armed forces who were either on leave or were lucky to escape the alien attacks on military bases.

As a result of this the Resistance is a diverse group with many skills that will prove not only useful for survival but success against the aliens.

A list of members who are key to the resistance and have made important breakthroughs for the resistance's cause:

Colonel Porter: Head of the Boston chapter of the Resistance and one of the few remaining veteran soldiers.

Captain Dan Weaver: Leader of the second Mass, a seasoned war veteran who lost most of his family in the initial attack.

Tom Mason: Weaver's second-in-command and representative for the civilian population. His use of military history and compassion have helped the resistance through some hard times.

John Pope: Originally a leader of a gang of bandits, he becomes a prisoner of the resistance, but eventually proves himself and becomes their munitions expert. He and Matt Mason are credited with the creation of the first effective amunition against the mechs.

Loudres: A first year med student before the attack and also the keeper of the resistance's spiritual well-being; offering a counsel and a sympathetic ear to those struggling with the war.

Dr Anne Glass: The second Mass' doctor and potential love interest for Tom. She discovered the truth behind the Harness.

Uncle Scott: Anne's uncle and teacher of the Resistance Children. He discovered the Skitters' use of radio wave communication and helped invent the jamming frequency used against the aliens.

At the start of the series the Boston resistance is evacuating the City; the aliens have been using frequnt bombing runs on them, forcing them to flee. Under Colonel Porter's orders the Resistance breaks up into smaller groups, with the rest of the action taking place with the Second Mass.

Following the Second Mass the series focuses mostly on their survival and guerilla tactic which at first have little effect on the aliens. The humans remain inspired to keep fighting by Tom Mason, who reminds everyone that Earth is theirs, and not the aliens'.

The Second Mass soon plays host to a doctor who has a potential theory on releasing the victims of a Harness without killing them. Not only is the trial successful; it also provides the Mass with an alien prisoner for further study and eventually reunites Tom with his son Ben, who is freed when a group of captured harnessed children are brought in.

Midway through the series the Second Mass comes into conflict with the Seventh Mass whose leader has struck a deal with the Skitters; trading children in exchange for immunity from attacks. The Seventh Mass attempts to con the Second Mass into handing over their children under the pretense of protection from a large attack. The ruse is discovered, and the Second Mass is able to rescue the children and disband the Seventh Mass under threat they will kill them on sight if they find they have been trading with the aliens again.

In the finale the Resistance launches an attack on the alien base in Boston with newly invented Mech rounds that can destroy the alien robots. The attack and the resistance is almost destroyed by Rick; an unharnessed child still under the influence of the harness due it having been removed to late. He steals a key component to the Jamming device and flees to another harnessed child, who he tells all about the Resistance and their plans only for her to abbandon him since the aliens have no use for him. Fortunately, Tom is able to find Rick and retrieve the component wich is used in the device to repel a large extermination force sent to wipe out the resistance base. Tom later heads into the city, and along with Weaver, manages to seriously damage the aliens' structure.

This victory draws the attention of the alien leaders; the Slenders who send a harnessed human and a representative to intercept Tom and Weaver. The harnessed human reveals the aliens had not anticipated such strong resistance from an inferior race and this has interested them. They demand Tom go with them in exchange for releasing his son from the conversion prosess.